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Baldwin IV

…(Kroon-Vlaanderen), the German fiefs as Imperial Flanders (Rijks-Vlaanderen). Baldwin’s son—afterward Baldwin V—rebelled in 1028 against his father at the instigation of his wife, Adela, daughter of Robert II of France; two years later peace was sworn at Oudenaarde, and the old count continued to reign until his death.

Flanders

…held east of it (called Imperial Flanders, or Rijksvlaanderen, as part of the Holy Roman Empire). The Flemish counts enjoyed virtual independence from weak French kings during this time. The first dynasty of counts died out in 1119, but Flanders rose to the height of its power and wealth under…

Robert I

…father also invested him with Imperial Flanders, including the islands of Frisia west of the Scheldt. He thus in his own right and that of his stepson became ruler of all of Frisia (Zeeland) and was known among his Flemish countrymen as Robert the Frisian.